Since autism was first described in the 1940s, researchers have been hunting for its causes. In the beginning, most of the focus was on children’s environment and parenting styles. But since the late 1990s, scientists have increasingly looked to the brain for answers.
The search for abnormal brain signals began with studies of brain anatomy. In the early 2000s, researchers found that some autistic brains are larger than typically developing brains, especially in the early years of life. Other studies revealed that the autistic brain tends to grow faster in the first few years of life, then levels off or even shrinks in adolescence and adulthood.
More recently, scientists have turned to brain imaging to try to uncover the source of autism’s brain differences. One of the most common techniques is functional MRI, or fMRI. This allows researchers to observe which parts of the brain are activated during specific tasks.
Several small fMRI studies have found that, compared with neurotypical brains, autistic brains show less activity in the social cognition network. This network includes the regions of the brain that are important for understanding other people’s emotions, intentions and mental states.
These findings are in line with what we know about autism: that it is characterized by social deficits and difficulties with communication. But they don’t explain why autistic brains show these patterns of activity.
To try to uncover the underlying cause of these brain differences, scientists are now turning to a newer form of brain imaging, known as functional connectivity MRI, or fcMRI. This technique allows researchers to see how different regions of the brain are connected to each other and how these connections change over time.
Early studies using fcMRI have found that autistic brains show abnormalities in the way different regions are connected to each other. For example, one study found that autistic brains show reduced connectivity between the amygdala (a region important for processing emotions) and the rest of the brain.
These findings are still preliminary, and it’s too soon to say whether they will lead to a better understanding of the causes of autism. But they offer a promising new direction for research, and they provide a first glimpse into the disrupted brain networks that may underlie autism’s social and communication deficits.
Scientists believe that understanding the brain signals that are disrupted in autism could lead to earlier diagnosis and new treatments for the condition.
Autism spectrum disorder (ASD) is a neurological condition that affects social interaction, communication, and behavior. ASD can be mild or severe, and symptoms can vary from person to person.
Currently, there is no single test that can diagnose ASD. Diagnosis is based on observation of symptoms and is often made after a child has reached school age. This can make it difficult to identify ASD early, when intervention may be most effective.
Scientists are now using brain imaging techniques to try to understand the underlying brain changes associated with ASD. This may help to develop new ASD biomarkers that could be used for earlier diagnosis.
One study used magnetic resonance imaging (MRI) to compare the brains of children with ASD and typically developing children. The researchers found that the brains of children with ASD were different in several key areas.
These differences included:
• Reduced surface area
• Abnormalities in the shape of certain brain regions
• differences in the way brain regions are connected
• Reduced brain activity in certain regions
Another study used a brain imaging technique called functional connectivity MRI (FCMRI) to examine the brain networks of children with ASD. FCMRI looks at how different brain regions work together.
The study found that children with ASD had less connectivity between certain brain regions than typically developing children. This reduced connectivity was most evident in the brain regions responsible for social and communication skills.
These findings suggest that the brain changes seen in ASD may contribute to the social and communication difficulties that are characteristic of the condition.
Brain imaging studies like these are providing new insights into the brain changes associated with ASD. This research is essential for developing new diagnostic tools and treatments for ASD.